1. Field of the Invention
The present invention relates to the field of bras, particularly to bra engineering.
2. Background Information
The bra sizing system currently used in ready to wear consists of two measurements; the circumference of the ribcage, and cup size.
Normally production samples are made for size 34B/75B, the difference between the ribcage and full bust circumference determines cup size.
In “The Bra Fitting Bible”, Emma Scott teaches “The goal with any cup sizing predicting method is to determine the volume of breast tissue such that it could be assigned a standardized cup letter. Cup letter is a description of how a semi-circular mound of breast tissue, of a set volume appears in size relative to a ribcage, of a set girth that it is attached to. The malleable nature of breast tissue makes calculating an accurate breast mound volume difficult. The average ribcage method of calculating cup size measures the breast inclusively with the ribcage and then calculates the breast protrusion by subtracting the ribcage measurement from the total bust measurement. The over breast method of calculating cup size measures the protrusion of each individual breast. By relating the measured protrusion of a breast to establish mathematical rules regarding spheres, breast attributes can be assigned to a breast mound if it is modeled as a half sphere.
The theory behind bra sizing is grounded on the premise that measurements that are taken from a breast can be used to create a spherical breast mound model, knowing that breast tissue is malleable and will be able to take on a spherical form.
A semi-circular shape is the most accurate way to analyze a multitude of breast tissue volumes across a population and then categorize them into sizes so that a ready to wear sizing system is even possible. Even though a good percentage of breasts are not naturally spherical in nature, this is an aesthetic shape that most breast tissue can be gathered and manipulated into. For the purpose of calculating bra size, the breasts are regarded as two half spheres sitting on a ribcage.
If the over breast measurement is adjusted so that the breast model is spheroid rather than the original sphere, the mathematical calculations will be different from those presented below. It is not necessary to discuss the mathematical relationships of spheroids in this text but it is important to note such calculations do exist.
The spread of the breast mound is limited by the chest width between the armholes. The base half sphere model of breast mound can grow radially only to the point of the arm hole. At this point the base of the sphere can no longer spread and all growth must be manipulated forward and away from the armholes. Extremely large breasts will have too much volume for the standard sphere model of bra cup. Although the sphere model is suitable for calculating volume, it does not reflect the shape that a cup is forced to take on when the volume increases beyond the limits of the upper body. Once the base cup has expanded to the full extent of the upper body width, the remaining cup sizes will share the largest available base. From this point on the cups will begin to be less half sphere like as their base diameter remains the same while the volume continues to grow.
The chart below details the core attributes of breast mound spread and protrusion that is relevant to bra sizing.
Mathematical Relationships of a Circle:                1. Circumference=3.14×Diameter        2. Diameter=Circumference÷3.14        3. Radius=Circumference÷6.28        4. Radius=Breast Mound protrusion        5. Breast Mound Diameter=Distance Over Mound×2÷3.14 Calculates the Base Spread or the Diameter of the Breast Mound        6. Breast Protrusion=Distance Over Mound÷6.28 Calculates Breast Mound Protrusion        7. Volume=0.26×Diameter        8. Cup Volume=0.26×Breast Mound Diameter×Breast Mound Diameter×Breast Mound Diameter        
Because we know the breast model is a half sphere, certain characteristics can be mathematically calculated. For example, if we know the diameter of a circle we can use a formula to calculate the circle's circumference. Likewise, if we are aware of the circumference of a circle we can calculate the diameter or the radius. In relationship to a breast mound, if we know the distance over the mound we can calculate the spread or diameter of the breast mound, or the protrusion of the breast mound. Most importantly, if we know the distance over the breast mound, we can calculate the diameter of the mound and if we know the diameter of the mound we can calculate the volume.
See FIG. 20 Breast Mound Spread and Protrusion.
The lettered labeling system for bra cup is based on breast tissue being gathered into a semi spherical shape so that mathematical attributes can be determined. The half sphere is important as a mathematical model for volume calculation. The circle is therefore a key geometric shape in bra design. Bra cups gather and collect breast tissue into predetermined semi-circular base and protrusion mounds applicable to a specific cup size for a given band. Breast tissue volume is labeled relative to the chest cavity it is sitting on. A breast volume of 500 ml or 2 cups will appear large on a ribcage that measures 61 cm or 24 inches and be labeled a 28F. That same volume will not appear as large on a 81 cm or 32 inch ribcage and will be labeled a 36B. To fully understand bra sizing it must be understood that it is neither volume nor bust circumference that dictates cup size.
Since there are no definitive industry standards for cup size and volume, volumes are considered to reflect an average range for standard bra sizes, and may differ slightly from product line to product line. The theory of size change however, is the same across the lingerie industry. Identical breast tissue volumes on different ribcage frames are labelled differently and are called sister sizes. Any volume of breast tissue will have a multitude of cup sizes that it could technically fill, but only three of these cups will be on a band that comes “close” to “fitting” and only one of the band and cup combinations will be the correct bra size.”
Industry bras are designed to contain the breast tissue by approximating volume and using a tight breast root diameter trace and around the body measurement to support the breasts.
From “The Origins and Evolution of the Bra” by Shin;
“In addition to breast measurements, the breast root can be defined as the crease line where the breast forms on the chest. Every women's breast root are unique and it is essential that the wire curve is matched with the breast root otherwise the wire will create discomfort. However matching the right shape for the individual customers is largely impossible to mass production practice. A good fit bra which is comfortable, uplifting and supporting simultaneously depends on finding a wire which closely matches the shape of the breast root of the wearer.
The development of the pattern drafting system is considered one of the key elements of the development of ready to wear clothing in the 19th century. Godley 1997 emphasizes that the original force behind the development of ready to wear clothing is not the invention of the sewing machine, but the development of standard sizes. In elaboration of Godleys point, Aldrich (2000) identifies three important factors in this development:
The standardization of measurements;
The improvement of pattern drafting; and
The adoption of a grading system.
As a consequence, the development of a basic block for faster production among tailor was inevitable in order to survive a fast development area of commerce. Since the 19th century patternmaking has continued to develop into more organized formats and now there are basically four different pattern making systems available.
The four different patternmaking methods commonly used by fashion designers and patternmakers in the industry and educators in the education field are:
1. Draping
2. 2. Pattern drafting
3. 3. Flat patternmaking
4. Knock off
The draping method involves creating the pattern pieces by applying fabric directly onto the three dimensional dress form.
Pattern Drafting
Direct pattern drafting or pattern drafting is a system of patternmaking that uses a combination of ease allowance and body measurements taken from a dress form or fit model to create patterns including basic, foundation, and fashion patterns (Joseph-Armstrong, 2005).
The draping method involves creating the pattern pieces by applying fabric directly onto the three dimensional dress form. The advantage of using the draping method for patternmaking is that designers or patternmakers can transfer their two dimensional sketch to a three dimensional sample directly onto the dress form, which gives a reasonable view of the finished look of the design without having to cut and sew sample garments. The disadvantage of this method is that finding fabrics with an equivalent hand feeling/drape to a fashion fabric for a finished garment can be difficult and costly. Unfinished plain weaved cotton, or muslin, is normally used in the fashion industry and educational institutes for draping methods in order to lower cost, but often designers prefer to use fashion fabrics for better results. The expense in terms of material and time is why this ‘ideal’ method of developing design ideas is usually reserved for higher price fashion such as designer brands or ‘Haute Couture’. It is common practice in the fashion industry to combine the draping method and the flat patternmaking method for faster production.
For example, Jaffe and Relis (2000) recommend using the draping method to develop the basic block, and then use the basic block for flat patternmaking.
Knock-Off
The aptly termed ‘knock-off’ is a frequently used method of creating patterns by copying ready-made garments. It is commonly used when a manufacturer wants to take advantage of a well publicised hot fashion item, sometimes from a famous designer label, without the need for lengthy preproduction time before the season ends or sales cool down (Joseph-Armstrong, 2005).
Underwear designers and patternmakers from the well-established bra manufacturing retailers and brands seldom knock off ‘designer bras’. Instead, they are often encouraged to copy, recycle, or slightly alter existing patterns, or knock off their direct competitors' bras. This is because: 1) designer labels cater only for a specific target consumer group which is a very small part of the multi-million dollar bra industry, 2) the main purpose of the bra is for support not for fashion (although there have been changes in recent years), and most importantly 3) the copy/recycle/alteration/knock-off does not require professional training or experience in bra patternmaking. Therefore, this has been a quick and easy solution for the bra industry where well trained and experienced patternmakers are difficult to find. Whilst there are some innovative designers who create innovative products by adopting an out-of-box approach, the industry continues to predominantly use the “copy/recycle/alteration/knock-off” method(s). Consequently, this has stifled some creativity and innovation in bra patternmaking which requires a solid understanding of the relationship between body measurements and pattern.
The need for further development of the basic block led to the development of the concept of the intermediate block. The intermediate block, or foundation, is developed from the basic block to enable easier and faster pattern manipulation. Use of the intermediate block maximizes the utilization of flat patternmaking because it enables patternmakers to produce patterns for a variety of styles within a short period of time.
Whilst bras containing no wire, such as sports bras, can be developed from a basic bodice, using a basic bodice for underwired bra drafting remains a highly technical task.
Garment fit depends on five elements: (1) Grain (2) Set (3) Line (4) Balance and (5) Ease (Brown and Rice, 2000). These five elements are normally used as the evaluation tool for outerwear fit where the laws of gravity impact upon the whole garment. As the bra is resisting gravity which pulls the breast downwards it creates an undesirable shape as well as potential muscle and posture problems, particularly as the breast size increases. Since the bra is a foundation garment, it is required to support the weight of the breast. Therefore, bra making means not only producing an aesthetically pleasing appearance, but also making a functionally supportive garment. The bra doesn't have ‘ease’ to assist with evaluating proper fit. This is replaced by ‘tension’ because the bra wing is largely made up of stretch materials which require taking the ‘ease’ of a total of 10 cm-15 cm from the actual ribcage circumference. Consequently, in order to accomplish the goal of a good fit and an aesthetically pleasing bra, consideration needs to be given to the type and properties of the construction materials. As a result, a perfect fit is unlikely at the first attempt because various bra materials and the direction of cut make it difficult to achieve an immediate perfect fit even for very experienced patternmakers.
The Underwired Bra Patternmaking Process
The underwire itself can be categorized by three different centre heights; lower centre, medium, and full cup wire, and various wire gauges are available as well as a multitude of wire shapes. Typically, underwired bra pattern pieces consist of a bra cup, front centre, side panel, and wing. The front centre and side panels together are called a ‘cradle’. Normally the front part of the bra is rigid and the back section (wing) is constructed of stretch material. When a wire is selected for bra design, there are three things which should be considered; curve, tension and the length of wire. Bra band patternmaking starts with the shape of wire, and bra cup patternmaking depends on the wire centre height along with the breast measurements.
“Ideal” Body Measurements for 75B and Direct Drafting of Full Cup Bra Body Measurements.
The basic bra sizing system currently used consists of two measurements; the circumference of the ribcage, and cup size. Normally, production samples are made for size 34B/75B. The metric system is used for pattern drafting since 75 cm is a more exact ribcage measurement whilst a formula should be used for the imperial sizing system (34B). The difference between the ribcage and full bust circumference determines cup size. To some extent, 34B seems too small to be a standard size for patternmaking when commercial sizes range from 28-AA to 56-FF, but 34B “ideal” is not an entirely arbitrary designation because it represents the bust line considered most pleasing to the ‘artistic’ eye of most dress/outerwear designers—although there is clearly room here for disagreement!
Difference Between Ribcage and Full Bust Size
Difference between ribcageCup sizeand full bust circumference(US sizing system)10cmAA12.5cmA15cmB17.5cmC20cmD22.5cmE25cmF
Ideal Breast Measurements for 34B/75B
WHERE TO MEASUREMEASUREMENTSBreast inner curve length9cmBreast outer curve length10cmBreast depth8.5cmDistance between bust points18cm
Patternmaking for an underwired bra consists of two basic patternmaking procedures: These are band drafting (SEE FIG. 19) and cup drafting (SEE FIG. 18). The band pattern shape depends on a wire curve and the cup pattern shape depends on breast measurements (breast inner curve length, outer curve length and breast depth). The following method is for a full cup underwire bra (a 215 mm length full cup wire was used for the sample patternmaking illustrated here).
Band Drafting
Finding the Centre of Wire
First of all, it is essential to identify the centre of the wire, which works as a fulcrum. Each end of the underwire tip should point directly towards an appropriate body point. The inner wire end should be directed towards the centre of the pit at the base of the neck and the outer wire end should point directly to the point of the shoulder. After defining the centre of wire, draw a horizontal line and a vertical line on a piece of paper. Place a wire by matching the inside curve of the centre point of the wire with the X-axis at the same time matching the inside of the inner wire end point with the Y-axis. Marking the centre of the wire can be done simultaneously or after marking the guideline.
Marking the Guide Lines
The total circumference of the bra band for 75B (excluding hook and eye tape) is around 60 cm. For this paper, 29.5 cm was used for the half of bra band width. The cradle width is nearly half of the bra band width. 15 cm was used for this paper. The width of the gore indicates the closest distance between the breasts or cups. It is important to note that there can be differences in this measurement between ethnic groups as well as individuals. 1 cm is used for the purposes of this paper.
Tracing Wire and Opening the Wire
Place a wire by matching the centre of wire to the horizontal guide line and trace the whole wire. After tracing, open the half of wire on the armhole side and trace the open shape of wire. Opening amount (a) between the original tip and open tip is between 1 cm and 2 cm. The amount depends on the shape and tension of the wire used. The purpose of this procedure is to mimic the open and bent shape of the wire when the bra is worn on a three-dimensional human body. 1.7 cm was used for the purposes of this paper.
Allowance for Wire and Wire Play
An 8 mm allowance (b) for both movement ease and sewing (bar tacking) is added on both wire tips and 6 mm wire play (c) is added. Wire play is literally where wire resides.
Mid-Point of Cradle Height
The mid-point of the cradle height (d) depends on the underband elastic tape width. In order to prevent flipping or a ‘folding’ effect on the mid-point of the cradle when a bra is worn, wire casing and underband elastic tape should be overlapped and sewn together. Therefore, when a 1 cm width of elastic tape is used, the mid-point height of the cradle should be 1.3 cm and when a 1.2 cm width of elastic tape is used, the mid-point height of the cradle should be 1.5 cm.
Wing Drafting
The starting point for wing drafting is finding the amount of wing drop. As the opening amount (a) gets bigger, so the wing drop (e) gets bigger. Some patternmakers suggest using a set amount for both opening of the wire and dropping of the wing.
The back of the wing height (f) is same as the hook and eye tape width since it is attached to a hook and eye tape. A 3.2 cm hook and eye tape was used for this sample. Coincidentally, a 3.2 cm drop of the back wing was also used for this paper.
Finishing the Band Drafting
The other lines are style lines and can be changed according to the design sketches. This is of course a matter for the patternmakers own judgement.
Measuring Joining Seam/Preparation for Cup Drafting
After finishing the bra band drafting, the length of the seam line where the cup will be sewn together should be measured. Each half of the curve is labelled as (g) and (h) for explanatory purposes.
Cup Drafting
(A) Lower Cup
Guide Lines
Draw a vertical line for the breast depth of 75B (8.5 cm) and divide into two different lengths (5.5 cm and 3 cm) with a horizontal line.
Upper Curve Lines of Lower Cup
In order to achieve the breast inner curve length (9 cm) and breast outer curve length (10 cm) draw straight lines of 8.8 cm and 9.8 cm from B.P to each side of the horizontal guide line. Complete the curve lines by following the guide measurements (10 mm for centre side curve and 7 mm for the armhole side curve). Measure the curve lines in order to make sure the finished line lengths are correct.
Lower Curve Lines of Lower Cup
Once the upper half of the lower cup is finished, drawing the lower half of the lower cup is relatively easy. Draw two straight guide lines by connecting the two end points of the upper line with the 3 cm point on the centre guide line of the cup. Draw curve lines by following the guide measurements (8 mm for centre side curve and 9 mm for the armhole side curve). Measure the length of lower curve lines (‘a’ and ‘b’ as shown in FIG. 19) and write their lengths alongside both curve lines for future reference.
Splitting the Lower Cup
The lower cup can then be split in half and 4 mm of fullness can be added on the centre of the line. When two layers are used for bra construction, the inner layer can have a split for fullness and the outer cup, normally cut with a stretch material, can be used as one piece.
(B) Upper Cup
Joining Seam Length
Drafting the upper cup starts by dropping the centre point by 5 mm. The bigger the amount is, the ‘pointier’ the bra cup projection is. Draw a smooth curve which is close to the straight line to each side. Each side length from the bust point (B.P.) should be the same as the lower cup length (9 cm and 10 cm) because they will be sewn together. The armhole side of the upper cup is lifted 4 mm from the guide line in order to make the smaller cup edge/neck line length.
Upper Cup Height
Each side of the upper cup height (c and d) is calculated by subtracting lower curve lengths from the cradle joining seam. The following is a simple formula for each side of upper cup height length.c=g(bra band)−a(bottom cup)d=h(bra band)−b(bottom cup)
Shoulder Strap
A 1 cm width of shoulder strap was used for this sample. Other measurements are considered as design lines. After completion of the pattern drafting process, matching and reshaping of the pattern pieces is required. The seam allowance and notches are added afterwards.
Sample Work Drawing with Measurements.
It might be helpful here to provide some explanation of the industry practice in relation to how designers create a work drawing/technical sketch in order to instruct patternmakers. Generally, the designer measures an existing bra which is similar to what she wants to create and fills out the measurements along with a flat sketch so patternmakers can make patterns which will project the same fit. This practice is called preparing a ‘knock off’ and is one of the most popular methods used by industry fashion designers for both outerwear and under wear.”
According to Wikipedia brassiere measurement refers to determining what size of bra a woman wears and mass-producing bras that will fit most women. Bra sizes usually consist of a number, indicating a band size around the woman's torso, and one or more letters indicating the breast cup size.
To mass produce bras, manufacturers size their bras to a prototypical woman called a “fit model”.
A fit model is used by an apparel company as the “ideal” body type for whom the bra is designed. The fit model is chosen on her body size and proportions with the goal of representing all of the people in the target market.
Once the fit has been perfected on these models, the patterns are graded and the bra is made. The traditional bra cup is not shaped to conform to variations in the human female breast. In prior art, the cup of the bra angles upwardly and outwardly from an underwire (or wireless) attachment point, leaving little allowance for differences in breast shape, spacing and body type.
Manufacturing a well-fitting bra is a challenge since the garment is supposed to be form fitting but women's breasts can vary in volume, width, height, composition, shape and position on the chest. Manufacturers make standard bra sizes that provide a “close” fit however even a woman with accurate measurements can have a difficult time finding a correctly fitted bra.
Manufacturers may size and design bras to different standards of an “ideal.”
The fit model is the determining factor of the fit of the bra. Even if a woman has the exact same measurements as the fit model the bra may not fit as current industry measurements don't account for breast and body variations.”
In Industry, bras are manufactured based on a standard diameter measurement based on breast volume and a standard projection measurement based on the relationship between the underbust measurement and the overbust measurement. Based on these two industry standard measurements, the choices the customer has in actual fit variation is limited.
According to Foundations Revealed:
In the industry a single “core size” block is “graded” (adjusted) to produce the other sizes in the range.
The bra block is based on the assumption of an aesthetic optimum shape, a wire that is principally semicircular, a uniform diameter increment between wire diameters and a uniform volume increment between wire diameters.
Underwires are designed to have some spring. Made out of heavy gauge wire, sheet metal or plastic, they splay or spread wider once a bra is put on and fastened. Then they return to their original shape when the bra is taken off. This springing or splay gives additional support to your breasts. If your breasts are wider than the splayed diameter of the underwire, over time the pressure and weight of your breasts can cause an underwire to break in half. Wire breakage can also occur if your band size is too small and thus over-splaying the underwires.
Breasts have a natural “crease line” (inframammary fold) where the underwire should fit comfortably against the ribcage. The diameter of the underwire is too small if the underarm end is poking breast tissue, or catches the arm as it moves forward. The diameter of the underwire is too large if the underarm end is poking into the armpit. The best underwire is one that encircles the breast, giving a more rounded and defined look. Women short in stature usually find that underwires poke them under their arms. An instant solution is to select demi cup bras—the wires are shorter and thus will not poke.
Cups give a hemi-spherical shape to breasts and underwires give shape to cups.
The breast volume is a very essential dimension related to bra design. Although the volume of a breast can be visualized using the 3D body scan data, it is very difficult to obtain accurate natural breast volumes because the borderline of the breast is not clear enough to be defined separately from the body surface. Medical research studies have investigated breast volume measurements for asymmetry assessment or breast surgery. In contrast, there is limited information relevant to the investigation of the 3D breast shape in the apparel industry. Moreover, many previous studies ignored the curved character of the 3D breast base. Most of the studies assume that the breast base is a circle and the breast bulk is a cone (Lee et al., 2004).
In Foundations Revealed “How to Make a Bra” it is taught to take a breast root trace with a flexicurve, you have to make sure the flexicurve (measuring device) is up against the point around where your breast tissue joins the chest wall. This is the same point around the breast where the underwire of a correctly fitting bra should sit, not on the breast tissue (pain) and not away from the breast (poor fit).
In “Wires 101”/The Lingerie Addict blog:
“An underwire is an artificial, idealized form of the breast root. The root of the breast is where the breast joins the body.
Underwires are narrower than our breasts, but once put into a bra the fabric sides of the bra pull them out. The sides and the cup form a cantilever which lifts the breasts upwards from the base—which is why you shouldn't need the straps of your bra for much support.
Most women have one breast larger than the other, but wires of course, are identical providing a more symmetrical base. The main function of the underwire is to push the breast into a certain shape. The breast is contained inside the wire outline and the breast volume pushed into the wire outline and the breast volume pushed into a chosen direction to give a certain appearance or fashion shape for the specific bra. Wires provide support in combination with the cradle and cup of the bra. Different wire types are intended to provide different shapes. There are three main types of underwire shapes but many subtle variations are found within each type. The main ones are day bra, plunge, and strapless.”
It is instructed in the industry to fit underwires, the same underwires are used for the cups of sizes 36A, 34B, 32C, 30D etc. . . . so those cups have the same volume. The reference numbers of underwire sizes are based on a B cup bra, for example underwire size 32 is for 32B cup (and 34A, 30C . . . ). An underwire size 30 width has a curvature diameter of 3-inch ⅚≈9.7 cm and this diameter increases by ⅓ inch≈0.847 cm by size. The table below shows volume calculations for some cups that can be found in a ready-to-wear large size shop.
UnderwireBra sizeBra sizeCupVolume ofWeight ofsize(US system)(UK system)diameterone cupboth breasts3032A 30B 28C32A 30B 28C 9.7 cm 240 cc0.43 kg (3 in ⅚)(0.51 US pt) (0.95 lb) 3234A 32B 30C34A 32B 30C10.6 cm 310 cc0.56 kg 28D28D(4 in ⅙)(0.66 US pt) (1.2 lb)3436A 34B 32C36A 34B 32C11.4 cm 390 cc0.70 kg 30D 28E30D 28DD(4 in ½)(0.82 US pt) (1.5 lb)3638A 36B 34C38A 36B 34C12.3 cm 480 cc0.86 kg 32D 30E 28F32D 30DD 28E(4 in ⅚)(1.0 US pt)(1.9 lb)3840A 38B 36C40A 38B 36C13.1 cm 590 cc1.1 kg34D 32E 30F34D 32DD 30E(5 in ⅙)(1.2 US pt)(2.4 lb)28G28F4042A 40B 38C42A 40B 38C14.0 cm 710 cc1.3 kg36D 34E 32F36D 34DD 32E(5 in ½)(1.5 US pt)(2.9 lb)30G 28H30F 28FF4244A 42B 40C44A 42B 40C14.8 cm 850 cc1.5 kg38D 36E 34F38D 36DD 34E(5 in ⅚)(1.8 US pt)(3.3 lb)32G 30H 28I32F 30FF 28G4444B 42C 40D44B 42C 40D15.7 cm1,000 cc1.8 kg38E 36F 34G38DD 36E 34F(6 in ⅙)(2.1 US pt)(4.0 lb)32H 30I 28J32FF 30G 28GG4644C 42D 40E44C 42D 40DD16.5 cm1,180 cc2.1 kg38F 36G 34H 32I38E 36F 34FF(6 in ½)(2.5 US pt)(4.6 lb)30J 28K32G 30GG 28H4844D 42E 40F44D 42DD 40E17.4 cm1,370 cc2.5 kg38G 36H 34I 32J38F 36FF 34G(6 in ⅚)(2.9 US pt)(5.5 lb)30K 28L32GG 30H 28HH5044E 42F 40G44DD 42E 40F18.2 cm1,580 cc2.8 kg38H 36I 34J 32K38FF 36G 34GG(7 in ⅙)(3.3 US pt)(6.2 lb)30L 28M32H 30HH 28J5244F 42G 40H 38I44E 42F 40FF19.0 cm1,810 cc3.3 kg36J 34K 32L38G 36GG 34H(7 in ½)(3.8 US pt)(7.3 lb)30M 28N32HH 30J 28JJ5444G 42H 40I 38J44F 42FF 40G19.9 cm2,060 cc3.7 kg36K 34L 32M38GG 36H 34HH(7 in ⅚)(4.4 US pt)(8.2 lb)30N 28O32J 30JJ 28K5644H 42I 40J 38K44FF 42G 40GG20.7 cm2,340 cc4.2 kg36L 34M 32N38H 36HH 34J(8 in ⅙)(4.9 US pt)(9.3 lb)30O 28P32JJ 30K 28KK5844I 42J 40K 38L44G 42GG 40H21.6 cm2,640 cc4.8 kg36M 34N 32O38HH 36J 34JJ(8 in ½)(5.6 US pt) (11 lb)30P32K 30KK6044J 42K 40L44GG 42H 40HH22.4 cm3,000 cc5.3 kg38M 36N 34O38J 36JJ 34K(8 in ⅚)(6.3 US pt) (12 lb)32P32KK
In Pattern School, it is taught the first step in determining your bra size, is your band size.
Cup size is estimated by subtracting the under bust (band) measurement from the bust measurement and comparing the result to the table below. Each cup has a fit range of 2.5 cm. Again this table is suited to Australian bras only. International countries use different values to achieve the same task. Be careful when ordering ‘equivalent’ bras from overseas because if they use inches then the larger sizes are not actually equivalent thanks to 1″ being 2.54 cm and not 2.5 cm!
Bust − UnderbustCup Size6.5 − 8cmAAcup8 − 10.5cmAcup10.5 − 13cmBcup13 − 15.5cmCcup15.5 − 18cmDcup18 − 20.5cmDDcup20.5 − 23cmEcup
Most wire manufacturers do follow the 1″ increment system meaning you will have one wire that suits several different cup sizes. For example, an 8D uses the same wire as a 10C or a 12B or 14A.
There is a great amount of debate in which purists say manufacturers should create bras to fit dozens of different shaped breasts and not just volumes. As it is there are several cups for each band size, and if we went to several shapes for each of those cup volumes for each band, the sheer logistics would spiral into an economic and practical impossibility.
The breast can change shape reasonably well for its volume and the amount of discomfort usually increases with the degree its distorted.
The “aesthetic optimum” consists of a lower quarter spheroid and a slightly elongate upper quarter spheroid. If your breast doesn't fit this shape, it means you end up looking for a bra cup to suit your breast volume which will have a wire that doesn't properly fit the natural curve of your breast. While there is some variation among manufacturers you will always be limited by the commercially viable standard sizes.
In Foundations Revealed, Mark Garbarcyk discusses the problem with bra grading in industry.
When we want to change the size of a bra pattern/block we could draft a new block for the new size, but in the industry a single “core size” block is “graded” (adjusted) to produce the other sizes in the range.
Take, as an example, the British bra size system. There are 16 cup sizes, AA-A-B-C-D-DD-E-F-FF-G-GG-H-HH-J-K-L, and 6 band sizes from 30″-40″. That makes 96 size options. Multiply that by 2 colourways (ie making white and black bras), and you and your company potentially have 192 different bras to make!
BUT what if you could use parts of one size bra in a different size bra? You can! Welcome to the world of bra CROSS GRADING.
If you take the cups and the cradle/underwires of a 34B bra and shorten the wings by the right amount, you have a 32C bra! Likewise, if you lengthen the wings on the cups and the cradle/underwires of a 34B bra by the right amount you will have a 36A bra! The same goes for other Cup/cradle sizes: the cups/cradle of a 38D bra are the same size cups/cradle as a 40C bra, and 36DD bra and a 34E bra, and so on and so on.
The table below shows cross grading using EN 13402 standard cup lettering.
Same cups and cradle30A32AA34AAASame cups and cradle30B32A34AASame cups and cradle30C32B34A36AASame cups and cradle30D32C34B36ASame cups and cradle30E32D34C36B38ASame cups and cradle30F32E34D36C38B40ASame cups and cradle30G32F34E36D38C40BSame cups and cradle30H32G34F36E38D40CSame cups and cradle30J32H34G36F38E40DSame cups and cradle30K32J34H36G38F40E
This cross grading system is also used for bra underwires: the underwires that are used in a 34B bra can also be used in a 36A bra, and so on.
The antiquated way in which women are measured for a bra is far from satisfactory, as it does not take into account the volume of the individual breasts and the variations in back size.
For UK sizing, measure in inches around the chest just under the breasts, then add 5″ if the measurement is an odd number or add 4″ if the measurement is an even number. This is your “Band size”—30, 32, 34, 36 and so on.
Now measure around the bust at its fullest part and take the band measurement (+5 or +4) away from this measurement. The difference—1″, 2″, 3″, 4″—indicates your cup size.
Emma Scott states in “The Bra Fitting Bible”: “For the purposes of breast analysis for cup size, bra cups are quite often reinforced with underwires. Underwires give added lift to breast tissue and keep the cup firmly against the ribcage Many women will complain that the underwires are uncomfortable and that they dig into the flesh.
Usually underwire discomfort is due to an incorrectly sized bra. An underwire will dig in when the bottom cup diameter, that is directly related to the cup volume, is too small. Choosing a larger cup size will solve this problem.
A good gauge of breast cup fit is to judge how the centre of the bra sits on the ribcage.
The portion of the bra that sits between the cups is referred to as the bra bridge (or gore). The bra bridge should sit flat against the sternum.
Bras are engineered to fit flat against the ribcage. If the bra bridge sits away from the chest wall, then either the band is too large, the cup is too small or a combination of both is wrong.
According to Wikipedia bras are one of the most complex pieces of apparel. There are lots of different styles, and each style has a dozen different sizes, and within that there are a lot of colors. Furthermore, there is a lot of product engineering. You've got hooks, you've got straps, there are usually two parts to every cup, and each requires a heavy amount of sewing. It is very component intensive. From 60-70% of bras sold in the United Kingdom and the United States use underwire in the cup. The underwire is made of metal, plastic, or resin. Underwire is built into the bra around the perimeter of the cup where it attaches to the band, increasing the rigidity of the bra. The underwire improves support, lift and separation. Wirefree or softcup bras support breasts using additional seaming and internal reinforcement. Some types of bras like T-shirt bras utilize molded cups that eliminate bra seams and hide the woman's nipples. Others use padding or shaping materials to enhance bust size or cleavage.
There is an increasingly wide range of brassiere styles available, designed to match different body types, situations, and outer wear. The degree of shaping and coverage of the breasts varies between styles, as do functionality, fashion, fit, fabric, and color. Common types include backless, balconette, convertible, shelf, full cup, demi-cup, minimizing, padded, plunge, posture, push-up, racerback, sheer, strapless, t-shirt, underwire, unlined, soft cup, and sports bra. Many designs combine one or more of these styles. Bras are built into some garments like camisoles, single-piece swimsuits, and tank tops, eliminating the need to wear a separate bra.
There is also a wide range of body shapes and breast variations. A womans breast tissue affects the way a bra fits. Full, semi-full, shallow and deflated are some upper breast shapes. Self-supporting, semi supported, settled and pendulous are some breast positions. Conical, thin, omega are some breast shapes. Touching, separated, splayed, narrow set and wide set are some breast positions.
According to Her Room, when selecting a bra, it is important to know that a cup size on one band size is not equal to the same cup size on another band size. When a manufacturer grades his patterns to create different sizes for a bra style, he moves the bust points slightly wider with each cup size increase. B cup bust points are ½” farther apart than A cups. Bust points get ¼″ farther apart between B, C, and D cups, and ⅛″ farther apart with larger cup sizes.
An element of the proper fitting bra is the center panel, or gore. It is best if the center panel between the cups sits firmly against your chest.
In order to put some order into a product that has so many variations, the industry devised a sizing system to organize and categorize bras for fit, and manufacturing purposes. The system is based off of measurements of an original fit model and the variations in sizes (cross grading and sister sizes) are based off of that body type. If your body is not a variation of that “ideal” it will be difficult to find a comfortable bra. Bras are designed to fit tight to form and the engineering dynamics only work properly when all of the components are in sync. One variation can throw the engineering off and compromise the comfort of the bra.
From Bra Making Pattern School
“We need to understand the purpose of a bra. Firstly, and most importantly, the bra functions as a support device to limit the motion of the breast during activity. Secondly, the bra serves to redistribute the forces of breast weight to the back and shoulder.
A bra is supposed to lift the breast and take the weight off the ligaments preventing sagging and stretch marks. So how do we carry the weight of the breast. Typically, this has been done by encasing the breast volume in some form of cup and then positioning the cup in a specific position on the chest using straps or close fitting bodices like corsets. The cup needs to encase enough of the breast volume to hold it in place during the anticipated activity.
Unlike other areas of the body, the breast has undercut shapes that requires close fitting in order to create the supporting shape.
In pattern making, unless you surround the entire breast the only way to maintain closeness of fit is with a stiffened former called and underwire. An underwire is a device typically made of steel that is inserted into the garment to force it to stay in a predetermined, though mostly semicircular shape. With semicircular wires available in incremental sizes, how do we decide the shape of a bra? Should the bra conform to the natural shape of the unsupported breast? Once we support the breast its clearly going to change shape based on how its supported.
The breast can not only change shape but have its center of gravity moved up or down and side to side relative to the chest. The pursuit of aesthetic values over function have pushed breasts into shapes and positions they were never intended to go.
From the study “In Braless and Sports Conditions” Zhou Jie, Yu Winnie, NG Sun-pui state:
“Commercially available sports bras are classified into two different types—compression and encapsulation. The compression bra is designed to restrict movement of the breasts by compressing and flattening them against the body. The encapsulation bra is similar in appearance to everyday bras. It contains moulded cups that individually separate and support the breasts.